Fibroblasts derived from patients with diabetes mellitus have reduced cell growth potential in vitro. The basis for these alterations remains controversial since either environmental or genetic factors could be responsible. This grant proposes to characterize fibroblasts from diabetic subjects in terms of well recognized criterion used in cell culture. Growth measurements such as population doubling times and the length of S-phase in synchronized cells are being measured. Rates of protein synthesis and degradation with particular attention to collagen are being performed. The steps of collagen synthesis are being examined in greater detail by quantitating steady state levels of procollagen mRNA and comparing the rate of mRNA translation in the diabetic and control fibroblast. Since diabetes is a heterogeneous genetic disease, it is possible that these studies will identify a number of abnormalities in protein synthesis which may account for the retarded cell growth. Eventually, these abnormalities may serve as genetic markers which may aid in clinical classification of diabetes mellitus and give a more fundamental understanding of the disease.